1. Field of the Invention
The present invention relates to a marine drive, and in particular to a water cooling system for a marine drive.
2. Description of the Related Art
An outboard motor commonly employs a water cooling system to cool an engine of the marine drive. The cooling system draws water from the body of water in which the watercraft is operated. For this purpose, a water inlet of the cooling system often is located on a lower unit of the outboard motor. The water inlet desirably is submerged beneath the water at all times when the watercraft is in the body of water. A pump draws water through the inlet and a water passage within the lower unit and delivers the water to cooling jackets within the engine.
The water inlet and the associated water passage of prior outboard motors commonly lies on the side of the lower unit well above a nacelle of the lower unit which houses a transmission and propeller shafts. This prior location of the water inlet and water passage, however, poses several drawbacks. For instance, the water passage tends not to have a sufficient size to provide an abundant supply of water to the pump. Little room exists on the side of the lower unit for the passage. The size of the water passage also has tended to be sacrificed in prior outboard motor designs in order to increase the size of an exhaust passage through the lower unit.
The position of the water inlet also poses a problem when the outboard motor is mounted in a high position on the transom of the watercraft so as to run the propellers partially exposed. Under some mounting arrangements, the water inlet can lie either at or above the surface of the water when the watercraft is up on plane. The amount of water forced or drawn into the water inlet consequently decreases from its submerged position. This effect of course exacerbates the problem of providing an ample supply of water to the water pump.